Chaser



Apr 5, 1933- s. F. NEWMAN ET AL CHASER Filed Jan. 16, 1931 gwuentou SamuelFNeu/mah Patented-Apr. 25, 1933 UNITED STATES PATENT OFFICE SAMUEL F. NEWMAN AND JAMES G. HARPER, OF WAYNESBORO, QPENNSYLVANIA, AS-

SIGN'ORS TO LANDIS MACHINE COMZRANY, OF WAY'NIESBORO, PENNSYLVANIA, A

COBEOBATION OF PENNSYLVANIA CHASEB Application filed January 18, 1931. Serial No. 609,194.

This invention relates to thread cutting chasers and particularly to tangential chasers and the method of making them.

An object of the invention is to provide an improved thread cutting chaser of the tangential type on which the thread cutting serrations may be ground as well as one on which all clamping surfaces of the chaser may be ground.

A further object is to provide a chaser having clearances whereby it may be accurately clamped in a holding device.

A further object is to provide a chaser in which sharp corners have been beveled 01f to provide a chaser having an outline of such form as will insure perfect seating in a chaser holder.

Further objects and advantages will be come apparent as the description proceeds.

Figure 2, a section on line 2--2 of Figure 1, but on an enlarged scale,

Figure 3, a face view of one form of improved chaser,

Figure 4, an end view of a modlfied form of improved tangential chaser having a beveled base, a portion of its back cut away, with screw'threads formed upon its back, a portion of its upper end cut away and having thread serrations milled through its entire length and having a portion of its back adjacent the screw threads cut away to insure perfect seating of the chaser,

Figure 5 is a face view of the chaser shown in Figure 4,

In the drawing numeral 10 indicates a chaser for cutting parallel threads having a beveled base 11, a back 12' and having a beveled portion 13 between the beveled base 0 and the back 12 and having its back cut away to provide a seating surface 14 against which a cooperating face of a chaser clamp 15 seats.

The surface 14 is cut away at 16 to provide a clearance between the face of the clamp 15 and the chaser. A beveled or dove-tailed edge 17 is provided for engagement by the depending edge of the'clamp.

From the description so far given it should be clear that when the chaser is mounted in the holder block 21, a clearance will be provided at 22'and at 16 but that the beveled base 11 and the back 12 of the chaser will be firmly seated against the corresponding surfaces in the holding block. The clamp 15 will engage the chaser at the dove-tailed portion 17 and, against the face 14 so that the chaser is accurately positioned and firmly held in position.

The chaser shown in Figure 4, in addition to the cut-away portions 13 and 16 shown in Figure 2, has screw-threads 23 formed upon its back and has its upper extending portion cut away as shown at 24. The back of the chaser moreover has a cut-away portion at 25, so that the chaser seats against the chaser holder against surfaces 26 and 27 only; in other respects the chaser is similar to that shown in F igure'2. The chaser shown in Figures 4 and 5 is particularly adapted for threading very large work.

In all forms of the chasers all seating surfaces may be ground and also the thread serrations on the thread of the chaser so that accurate thread cutting serrations may be formed and furthermore a chaser is formed having seating surfaces which insure accu rate positioning of the chaser in the holding block and accurately securing it there by a holding clamp and in which clearances are provided to take care of any trash which may become deposited adjacent the seating surfaces.

It will be obvious to those skilled in the art that various changes may be made in our device without departing from the spirit of the invention and therefore we do not limit ourselves to what is shown in the drawing and described in the specification, but only as indicated by the appended claims.

Having thus fully described our said in- Vention, what we claim as new and desire to secure by Letters Patent, is:

1. A tangential chaser having thread cutting serrations on its face and having a back with a portion of its surface cut away to provide a beveled seat for a holding clamp and an additional portion cut away adjacent the A beveled seat to provide a clearance between the clamp and a portion of the chaser, a sur- 0 face on the first named cut-away portion, said surface seating against said clamp and having a beveled base adjacent the back, substantially as set forth.

2. A tangential chaser having thread cuttin serrations on its face and having a back wi i a portion of its surfacecut away to provide a beveled seat to receive a holding clamp and an additional portion cut away adjacent the beveled seat to provide a clearance between the clamp and a portion of the chaser, a surface on the first named cut-away portion, said surface seating against said clamp and having a beveled base adjacent the back, the corner joining the back and the bevel base being cut off to provide a clearance be tween the chaser and a holding block, substantially as set forth.

3. A thread cutting chaser having parallel thread cutting serrations on its face and hav.-- a ing mutilated screw-threads hobbed on its back, a portion of the chaser being cut away to provide a seat for a clamp, said portion being further cut away adjacent the seat to provide a clearance between the clamp and I the chaser, a surface on the first named cutaway portion, said surface seating against said clamp, said chaser having a beveled base, substantiallyas set forth.

4. A thread cutting chaser having parallel 40 thread cutting serrations on its face and having mutilated screw-threads hobbed on its back, a portion of thechaser being cut away to provide a seat for a clamp, said portion being further cut away to provide a clearance between the clamp and the chaser, the back of the chaser being further cut away adjacent the threaded portion to provide a clearance between the back of the chaser and a holding block, said chaser having a beveled base, the juncture. of the beveled base and the back of the chaser being cut off to provide a clearance between the chaser and a holding block, substantially as set forth. 7

In witness whereof, we have hereunto set our hands at l/Vaynesboro, Pennsylvania this 5th day of J anuary A. D. nineteen hundred and thirty-one. SAMUEL F. NEWMAN.

JAMES G. HARPER. 

